Introduction to Anaemia and Microcytic Anaemia Flashcards

Question

Iron (7)

Answer 1

Can exist in Fe2+ or Fe3+ state Iron is essential= -Oxygen transport- Hb, myoglobin -Electron transport- mito production of ATP Iron is potentially toxic and needs to be handled safely by the body= -Free iron can generate free radicals (Fenton reaction) -Iron needs a chaperone molecule

Answer 2

-‘Closed’ system -Only able to absorb small amount iron -Tiny amount in circulation moving to/from storage site to be utilized – by marrow -Turnover in plasma pool is fast (4mg in pool and move 20mg/day)‏ -Circulating iron is bound to transferrin -It is transferred to the bone marrow macrophages that regulate iron uptake by transferrin receptor expression -They 'feed’ iron to red cell precursors -Iron is stored in ferritin mainly in the liver

Answer 3

Functional iron= haemoglobin Transported iron= serum iron, transferrin + transferrin saturation Storage iron= serum ferritin

Answer 4

protein with two binding sites for iron transports iron from donor tissues (macrophages, intestinal cells and hepatocytes) to tissues expressing transferrin receptors (especially erythroid marrow) % saturation of transferrin with iron is a measure of iron supply= -reduced in iron deficiency -reduced in anaemia of chronic disease -increased in genetic haemachromatosis

Answer 5

Large intracellular protein Spherical protein stores up to 4000 ferric ions Tiny amount of ferritin is present in serum= reflects intracellular ferritin synthesis in response to iron status of the host Serum ferritin is easily measured but an indirect measure of storage iron Low ferritin means iron deficiency

Answer 6

1. Exhaustion of iron stores (ferritin falls) 2. Iron deficient erythropoiesis then starts (MCV starts to fall) 3. Anaemia then develops 4. Epithelial changes (late effects in other sites of the chronic lack of iron)= -skin -koilonychia -angular chelitis

Answer 7

Insufficient dietary iron to meet requirements Losing iron – usually blood loss (usually gastrointestinal but others eg menstrual, urinary) Malabsorption (relatively uncommon) see lecture on iron metabolism. Absorbed in the proximal small bowel (non haem iron needs acid environment for absorption)- coeliac

Answer 8

Menorrhagia Gastrointestinal=tumours,ulcers+NSAIDS Haematuria

Answer 9

-Average 30-40ml/month (but wide range) -Equivalent to 15-20mg/month -Average daily intake 1mg/day -Iron status precarious -Heavy menstrual blood loss >60ml I.e. >30mg iron/month

Answer 10

A small volume gastrointestinal blood loss can occur without any symptoms or signs of bleeding (5mls of blood a day would be 2.5mg iron and might go unnoticed) This can outstrip the maximum dietary iron absorption of iron and result in microcytic anaemia

Answer 11

Iron deficiency anaemia= symptom not diagnosis Iron absorption can be increased by iron supplements Iron replacement therapy may relieve anaemia symptom without treating the underlying problem Investigations essential to identify diagnosis Early surgery of GI tumours may be curative

Answer 12

-Aim of treatment is to normalize Hb and restore iron stores -Remember most of total body iron is in Hb -Ferritin (iron stores) will not rise till after Hb returns to normal -MCV will rise as new, well haemoglobinised red cells are made -Newly made red cells are reticulocytes -Rise in Hb is limited by the ability of the marrow to upregulate production of red cells= healthy marrow can increase Hb concentration by 7- 10g/l per week if well supplied with iron + rise less if other issues eg ongoing blood loss